index.php

<?php
session_start();

if(isset($_SESSION['login'])){
    header('Location: home.php');
}  


?>
<form id="login_form" action="connected.php" method="POST">
    <table>
        <tr>
            <th>Login :</th>
            <td><input type="text" id ='login' name="login"></td>
        </tr>
        <tr>
            <th>Mot de passe :</th>
            <td><input type="password" if='password' name="password"></td>
        </tr>
        <tr>
            <th></th>
            <td><input type="submit" value="Se connecter..." /></td>
        </tr>
        <tr>
            <a href="signup.php">S'inscrire</a>
        </tr>
    </table>
</form>